Battery Management Technology Could Boost EV Performance

Researchers are working on a math-based battery management technique that could dramatically cut charging times for electric vehicles, while boosting useable battery energy and power.

If successful, the new technology could do what material scientists have struggled to do over the past decade -- improve useable power and energy density by up to 25 percent and reduce recharge time of electric vehicles to a scant 15 minutes. The University of California, San Diego, working with Bosch Research and Technology Center and Cobasys LLC, hopes to have a production version of the battery management system as soon as three to four years from now.

The key to the improvements lies in the efficient use of existing battery chemistries. "The idea is, if you actually know where the charged particles are within the battery, then you can safely operate the battery right to its limit," Scott Moura, postdoctoral fellow at the Jacobs School of Engineering at the University of California, San Diego, said in an interview. "So you can maintain the same battery size and get more range and power out of it. Or you can reduce the size of your battery and cut your costs."

Researchers from the University of California, San Diego have teamed with Bosch and Cobasys to create a battery management system that would enable EV batteries to be charged to their limits. (Source: UCSD)

The new battery management technology would accomplish that by combining a mathematical model with the voltage and current measurements that are employed in today's battery management systems. By fusing physical measurements with predictions from the model, the management system could know where the charged particles are inside the battery, and avoid the "charged particle traffic jams" that typically occur during charging. As a result, it could facilitate faster charging and discharging.

"It's all because we can use scientific theory to estimate the important states that are internal to the battery," Moura told us. "Instead of relying solely on current and voltage measurements, which don't represent what's happening inside the 'black box,' we can predict where the charged particles really are."

That knowledge enables the battery management system to more completely charge the battery, and to do it faster. Moreover, it enables the battery to discharge more quickly, which translates directly to power.

The Jacobs School of Engineering is working with Bosch, which makes battery management systems, and with Cobasys, which makes batteries, using a $4 million award from the Department of Energy's Advanced Research Projects Agency -- Energy (ARPA-e). The funding is helping the team to develop estimation algorithms for electric vehicle batteries.

Development of the algorithms is dependent upon the battery's chemistry and could be different from manufacturer to manufacturer, Moura said. "You need to have a decent idea of the characteristics of the cells and of the battery itself," he said. The team is currently working on lithium-ion chemistries.

"What's fantastic about this partnership is that there is a product timeline," Moura said. "Within three to four years, we expect to have an electrochemical-based battery management system to supply to automotive OEMs."

Nearly 20 years ago I dealt with a unique charging algorithm. We'd take a 1Amp/hr battery (suggested charge rate of 100mA peak) and inject 2.5Amp into the unit for roughly 0.5sec. This was followed by multiple 10Amp discharge pulses on the order of 1mSec in duration. This cycle was repeated continuously and formed the basis for the charging process. The result was a 20 minute time required to charge a fully discharged battery to 100% capacity. In addition the battery was cool to the touch upon completion of the charging cycle resulting in the electroytes were not being stressed due to excess heat. Batteries could be cycled through the discharge and charging process for more than 2000 charge cycles prior to showing a 10% reduction in capacity. This algorithm was implemented on nickel-cadnium or lead acid batteries and to a lesser extent nickel metal hydride batteries. The discharge pulses acted to redistribute the charged particles within the electrolyte reducing resistance. Efficiency in a normal charging process typically drops off in a matter seconds after the charge current is initiated. Here the discharge pulses act to "reset" the operating point on the efficiency curve to a much higher level thus allowing for the rapid charging process at a much higher efficiency. Less heat and longer life! Haven't seen or heard of the technology since then.

Great idea, but where is the charging infrastructure coming from to enable these potential charge rates?

There's enough grumbling about the costs associated with putting in a 220V circuit in EV owners' garages, and the current rate of charge for existing technology is already capable of exceeding that source.

Even at an EV "filling station" the power feed required would be pretty remarkable. Which means even more expense and complications to create a point of load energy supply for them.

Good point about A123, naperlou. The weak electric car market was their undoing. And more are sure to follow. The "last men standing" in the saturated EV battery market will be those who have enough capital to hang on until vehicle sales start rising. As you point out, A123 struggled, even with government funding.

As Naperlou pointed out, Beth, this is a research project. Given that, if they could productize this in three to four years (as they hope), it would be a major success. In truth, it's a tricky undertaking. In essence, they are squeezing more out of a battery by operating it to its very limits, which can be dangerous to the life of the battery. Today's electric cars typically don't come close to the operating limits of their batteries because automakers don't want to "brick" them (consider the guy who bricked his Tesla battery early this year and was told a replacement would cost $40,000). To make this work, they need to understand every specific battery chemistry very, very thoroughly.

Thanks for the that context, Naperlou. I hadn't heard about A123 Systems and that's a huge ding for the battery industry and for the momentum around EVs. They were definitely touted as one of the pioneers with promising technology so it's disheartening to see them ending up in bankruptcy protection. Again, it speaks to the time-to-market pressures on startups in the industry, which are caught between needing to hammer out the very real technical and development challenges associated with this technology, but also feeling the heat from investors who want/need to see returns from a commercialized product.

Beth, that's an important point. For one thing, this is a research project. I have worked on DARPA projects in the past. If it is DARPA it is, by definition, more basic research and this probably further out. Frankly, this has not been done and the researchers are speculating at this point. That said, they might well make it work. On the other hand, in three to four years, the landscape may be completely different.

Timing is also important in light of events from yesterday. A123 Systems filed for bankruptcy protection. One of the hot battery makers in the US, funded with massive amounts of Federal money, A123 looked like a winner. One of the big problems they had was that the demand for electric vehicles has not materialized. Another area I noticed they were interested in was utility storage. They were a lithium ion maker, and I don't know how useful that technology would be at that scale. It was the automotive sector, though, that hurt them. Their assets are being picked up by Johnson Controls, who is a large supplier to the automotive sector. This is a technology that needs lots more work.

Definitely a much-needed technology development, but a commercial version in three to four years? That seems a bit long given how fast this market needs to move. Is it the algorthim the cause for such a protracted commercialization schedule or are there other factors impeding its release?

Some cars are more reliable than others, but even the vehicles at the bottom of this year’s Consumer Reports reliability survey are vastly better than those of 20 years ago in the key areas of powertrain and hardware, experts said this week.

As it does every year, Consumers Union recently surveyed its members on the reliability of their vehicles. This year, it collected data on approximately 1.1 million cars and trucks, categorizing the members’ likes and dislikes, not only of their vehicles, but of the vehicle sub-systems, as well.

A few weeks ago, Ford Motor Co. quietly announced that it was rolling out a new wrinkle to the powerful safety feature called stability control, adding even more lifesaving potential to a technology that has already been very successful.

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